The two wireless technology standards are targeted to support mobile and fixed location devices as defined by the next iteration of the Continua Health Alliance Design Guidelines. The alliance has selected Bluetooth low energy wireless technology (pending finalization of the specification) to enable low powermobile devices such as activity monitors and heart rate sensors to be used to monitor a user’s health and fitness levels. Additionally, Continua has selected ZigBee Health Care technology for low power sensors that can be networked in a variety of settings, and utilized in devices such as motion detectors and bed pressure sensors to enhance the daily living of those who require assistance aging independently.

…ZigBee standard enables powerful new wireless applications for safety, security, and control, ranging from smart energy to home automation and medical care to advanced remote control.

I've touched on this topic before outside of the blog, but a recent comment made me think that it could be appropriate to bring it up again. People enjoy some controversy, so what's better than putting different standards up against each other? I'll try to explain the differences and explain why BLE and ZigBee don't really step on each other's toes in my opinion:

First, I would argue that Bluetooth low energy has been designed as an ultra-low power PAN/BAN (Personal Area Network/Body Area Network), while ZigBee is more of a low-power LAN (Local Area Network). BLE was designed from the start as a star network around a portable device such as a mobile phone. This means that it has a quite simple network topology, but with nodes dropping off or coming onto the network dynamically as they (or the central device) move in and out of range. It should be easy to add nodes, since they all connect to the central device. ZigBee was designed from the start to support mesh networking. This has two purposes; it allows the ZigBee network to cover a large network area (hence the LAN moniker), and it allows flexible routing to deal with situations where routing nodes may become unavailable for some reason. This paradigm is more suited to relatively stationary networks, since it takes some time and effort to keep the routing information up-to-date.

Each standard has a couple of killer features that the other one doesn't have, and if you need one of them, the choice is pretty clear. For BLE, it's how BLE dual-mode means BLE piggy-backs on the huge installed base of Bluetooth devices. If you need to ultra-low power communication with a device that already includes Bluetooth (mobile phone, PC, PND, PMP etc.), then BLE should be your protocol of choice. On the other hand, if you need mesh networking to cover a large area, then ZigBee is a clear choice.

Power-wise, ZigBee and Bluetooth are quite different as well. Which one is the lowest power depends on the usage scenario. BLE uses a synchronous connection for it's connections; meaning that both master and slave wake up synchronously. This helps keep power on both sides low. ZigBee uses an asynchronous scheme, this means that the routers stay awake all the time. The power consumption of the routers is then relatively high, but the end-nodes can wake up at any time, send their data and not have to wait for a specific time slot. You need to look into the specifics of your use case to figure out which one would fit your needs better; there is no clear-cut answer to the question "Is ZigBee or BLE lowest power?"

There will surely be some overlap in application areas, as there is always some tendency to try to broaden the scope of standards, but overall Bluetooth low energy and ZigBee target different areas. They each have their own strengths and weaknesses. BLE will be able to communicate with billions of Bluetooth devices, but does not support mesh. ZigBee can cover large areas, but is not so well suited to ad-hoc networking and requires powered routers.

West Technology Research Solutions analyst Kirsten West, quoted by our sister publication eWEEK, said "Bluetooth low energy will be a significant contributor to the overall wireless sensor network market, representing nearly half of all shipments in 2015. The advantage to this new protocol is that it is totally optimized for low power battery operation."

“Bluetooth Low Energyisdesignedto compete with protocols like ZigBee in applications which require infrequent and short bursts of data communication. The advantage to this new protocol is that it is totally optimized for low power battery operation.”

Developers of ZigBee, a specification for building large networks of low-power radio transmitters, expect the first set of consumer products incorporating the technology to hit the market as early as the fourth quarter of this year.

"The great thing with this technology is it's slowly going to surround you -- whether you know it or not," said Bob Heile, chairman of the ZigBee Alliance, which includes more than 175 members, including large multinationals like Motorola, Philips and Samsung.

*Upcoming products, including several slated to be unveiled at the alliance's upcoming conference in Chicago this month, are *mostly tailored to home security. But backers of the technology expect it will eventually be deployed much more broadly, for uses like landscaping, automated meter reading, and home lighting systems.

“Low-power sensing and monitoring is a core competency of ZigBee and we are excited to help Continua build its technology roadmap and help expand the telehealth industry ecosystem,” said Dr. Robert F. Heile, chairman, ZigBee Alliance. “ZigBee Health Care gives care professionals and consumers the ability to connect an almost unlimited number of monitoring devices with ease while maintaining privacy.”